201206271209 vouzs

explained decrypted filler

seed 151

Metadata

Post ID: vouzs
Title: 201206271209 → 2012-06-27 12:09 on A858's clock
Posted (UTC): 2012-06-27 16:07:16
Timezone: UTC−4 · title 12:09 against posted 16:07 UTC
Author: [deleted]
Account: A858DE45F56D9BC9 main account
Subreddit: r/A858DE45F56D9BC9 the main subreddit
Category: F3 filler: 3DES(name/title) → GUID list, seed known
Size: 528 hex characters · 264 bytes
Cipher: 3DES-EDE2 (two-key Triple DES), ECB, PKCS7
Key: MD5(A858DE45F56D9BC9) = 34a14a42e98ff96095af56604e290cae (name)
GUIDs: 8
Filler GUID seed: new Random(151).Next(9) ✓ verified
Run: Run 8 (seed 593,707,075) (seed)
Draw: 2 · predicted N = 8 ✓
Machine boot: F 2012-05-15 18:59–19:19 (seed = uptime at app start)
Sources: community-archive, arctic-shift · body from community-archive
Links: Reddit · Arctic Shift · JSON
Score · comments: 0 · 0
Tags: automated (decryptable)2012Encrypted masked GUID listkey: namerun: seed

From the post to its content

As posted (encrypted)

348018C0E913461C 67F44A17182D2227 9D6685D80CC76DCB 113983CE1D00FD7B 37DB7777C3131951 3B423E0DF11184E5 1BDF46E2480AD578 799292210B96229D 0428CDD9487B623C DC1FC062CE6B1713 54369C7D1DBE03DF A15E9FE6FACAFF27 532DE76217031ADA D12F219EAA172FB2 A03C0F1FFCC431EF 4CF8C544AC1A3D9D 6B6DE542F71827E6 D574DB25B114FA6D 5521AC1DEDACED7D 7740535C1B6EE2A5 9B886E745CC2E338 3089DF62B8E77147 71D917C1090576AA 1839255CB6DF4723 8B7642610884B6BD D1E637B7490D23A4 805FEEF310501458 AC7DF1690AE7E87F 72D6A8AF94AB42B5 6C5043D43AD97FCD 961C1B00C2DABBBB D25C775DC9548E94 5DACFFBA8FF64DBD

Read the ciphertext. Strip whitespace: 528 hex characters = 264 bytes = 33 8-byte 3DES blocks.
Derive the key. Password = A858DE45F56D9BC9 (name). Key = MD5(password) = 34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key.
Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 8 GUIDs as hex (shown below).

Decrypted: GUID list

  1 020ee390-cced-58ff-bb8a-d29bf18fa633
  2 a7832550-96dd-1b12-80d6-01e0053f6e06
  3 ac162e5e-bcab-251c-9db9-4c1d6588e70e
  4 9b8b96a2-3a2e-7fcd-b650-169ba207cf6e
  5 7726857d-27b7-3903-a2c3-c33256f3e252
  6 2135527c-613b-4f64-86e6-89ec2ece8579
  7 007a01b2-bd34-5a72-98d1-77f62bbafc84
  8 3689ff89-9ca0-1a86-b3e6-fa56f57c2e05

Explanation

Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives 51273451. Exactly this sequence comes out of new Random(151).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID are Guid.NewGuid() output and carry no message.
Explain the count. This post is draw 2 of Run 8 (seed 593,707,075): new Random(593707075), Next(8,24) per post. The RNG predicts N = 8; the post has N = 8 ✓. The seed is the machine's uptime in ms when the app started (boot F 2012-05-15 18:59–19:19).
Conclusion. Filler. The content is fully explained by the two RNGs.

Metadata

From the post to its content

As posted (encrypted)

Decrypted: GUID list

Explanation

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